The invention relates to an arrangement having a shaft with an external splining of a limited length that is embodied at a shaft end, and a hub with an internal splining that extends essentially the length of the hub—the external splining and the internal splining engaging each other to permit a transmission of torque between the shaft and hub. A first axial securing means functions between the shaft and hub, preventing the hub from sliding further onto the shaft, and comprises a stop surface on the hub and a counterpart surface on the shaft or a part connected to it at the end of the hub oriented toward the main body of the shaft. A second axial securing means functions between the shaft and hub, preventing the hub from being pulled off from the shaft. It includes a securing ring that is situated at the end of the shaft and the end of the hub oriented toward the shaft end and that engages in radial recesses in the shaft and hub. The recesses constitute the contact surfaces for this securing ring on the shaft and hub. The invention also relates to a method for manufacturing a shaft for such a connection. Such connections are advantageous in constant velocity joint applications.
Known securing systems between a shaft and a hub with a ball track of a constant velocity joint are embodied such that a securing ring guided in a groove is provided between the shaft and hub and prevents the hub from coming off from the shaft in the axial direction. In this connection, there have up to now been two different structural embodiments of the groove in the hub. The first embodiment concerns a detachable shaft/hub connection and the second embodiment concerns a non-detachable shaft/hub connection. In this context, there is only one structural embodiment for a shaft with external splining, with one structural embodiment of an annular groove; the annular groove has two steep flanks of approximately 0°.
In the detachable embodiment of the shaft/hub connection, the securing ring prevents the hub on the shaft from coming off in the axial direction during operation of the constant velocity joint, whereas for repair or maintenance purposes, the structural embodiment is selected so that the hub can essentially be detached from the shaft. In the detachable variant, the securing groove in the hub has a flank closer to the shaft end with an angle of greater than or equal to 15°. The securing groove of the hub exerts the compressive forces on the securing ring so that the securing ring is compressed and the hub can be detached.
In the non-detachable embodiment of the shaft/hub connection, the securing ring prevents the hub on the shaft from coming off in the axial direction during operation of the constant velocity joint. The structural design is selected so that the hub essentially cannot be detached from the shaft. In the non-detachable variant, the securing groove in the hub has a flank closer to the shaft end with an angle of less than or equal to 6°. In this variant, the securing groove in the hub does not exert any compressive forces on the securing ring so that the securing ring is not compressed and the hub cannot be detached.
Consequently, according to the prior art, two different structural embodiments of the hub must be produced in order to achieve a detachable variant and a non-detachable variant. This sharply increases production costs because it requires two different variants to be manufactured and stored. The primary disadvantage lies in the fact that in production and assembly, it is very difficult to differentiate between the two hub variants if they have not been labeled beforehand as to whether they are “detachable” or “non-detachable”. It is almost impossible to visually differentiate between the detachable variant and the non-detachable variant because of the extremely small difference in the flank angle of the securing groove. Additionally providing an “identification groove” or another marking that is visible even after assembly incurs additional costs.
An arrangement with axial securing means is known from U.S. Pat. No. 5,536,101. In that case, the first axial securing means is comprised of the external splining end oriented toward the main body of the shaft, the end surface of the hub or the internal splining, and a plastic insert ring whose shape is altered by these splinings. The second axial securing means is comprised of a simple rectangular-section ring that rests against the end of the hub oriented toward the shaft end and lies in a simple rectangular-section groove in the shaft at the protruding shaft end. This second axial securing means can only be used if its spatial placement is freely accessible for assembly and disassembly purposes. This is not the case, for example, if it is necessary to join a shaft to a ball hub of a preassembled swivel joint that is closed on one side. This requires a self-locking securing ring that is preinstalled into the annular groove in the shaft.
JP 5-22089 B2 discloses an arrangement including a hub body and a shaft in which the hub body is embodied in the form of a bevel gear of a differential. In this case, the first axial securing means between the hub body and the shaft is completely eliminated since the hub body is supported axially against a housing in which the shaft is supported. The external splining provided extends all the way to the end of the shaft. Spaced a bit apart from the shaft end, an annular groove with an inclined flank is cut into the splined region. This makes it possible for the shaft, which has a securing ring inserted into the annular groove, to be inserted into the hub body. This elastically forces the securing ring with a round cross section into the annular groove and after the hub is slid on, the securing ring rests against an inclined flank of the hub in an elastically expanding manner so that the annular groove does not have to be accessible after the hub is slid into place. Since the annular groove is cut into the region of the hardened external splining, though, when the internal splining of the hub is slid into place, particularly in the case of a press-fitting, shavings can be pulled against the spline edges, which give rise to unpredictable and inconsistent assembly forces.
U.S. Pat. No. 4,077,232 discloses a connection between an internally splined sleeve and an annular disk element, the latter serving to axially clamp spring-elastic ring elements whose external splining engages with the internal splining of the sleeve. The disk body here also has external splining that engages in the internal splining of the sleeve and is axially secured by a securing ring that is held in recesses in the sleeve and disk element. The disk element has a journal projection that has a smaller outer diameter than the tip diameter of the internal splining of the sleeve and the root circle diameter of the short external splining of the disk element. Torque transmission between the sleeve and the disk element does not occur.
GB 855,282 discloses an arrangement of a hub and a shaft in which a securing ring with a round cross section engages in recesses in the hub and shaft, which are embodied close to the end of the hub oriented toward the main body of the shaft. In this case, an annular groove is cut into the full-depth external splining on the shaft while an annular groove is cut into the internal splining inside the hub, but the tooth height of this internal splining decreases significantly from the annular groove to the end of the hub oriented toward the main body of the shaft. The securing means thus described performs the axial securing in both axial directions.
DE 78 09 284 U1 discloses an arrangement comprising a hub and a shaft with an external splining and a hub with an internal splining in which at the end of the shaft, a transition cone is provided from the tip diameter of the external splining to a journal with a smaller diameter, the journal being embodied in the form of a screw journal. Inside the hub, spaced a bit apart from its end oriented toward the shaft end, the internal splining ends and an annular groove is cut into the hub. From the annular groove to the end of the hub oriented toward the shaft end, the inner diameter corresponds approximately to the root circle diameter of the internal splining. A nut is screwed onto the screw journal and rests against the nub. A securing ring with a circular cross section is situated between the transition cone on the shaft and a counterpart cone in the nut and lies in the annular groove in the hub.
DE 40 40 337 A1 discloses an axial securing means between a hub and a shaft, but does not provide any torque transmitting means, i.e. it does not provide any splining. A securing ring lies in recesses in the hub and in an annular groove close to the end of the shaft. The diameter of the shaft decreases between the annular groove in the shaft and the end of the shaft.